POK
log2f.c
1 /*
2  * POK header
3  *
4  * The following file is a part of the POK project. Any modification should
5  * made according to the POK licence. You CANNOT use this file or a part of
6  * this file is this part of a file for your own project
7  *
8  * For more information on the POK licence, please see our LICENCE FILE
9  *
10  * Please follow the coding guidelines described in doc/CODING_GUIDELINES
11  *
12  * Copyright (c) 2007-2009 POK team
13  *
14  * Created by julien on Fri Jan 30 14:41:34 2009
15  */
16 
17 /* w_log10f.c -- float version of w_log10.c.
18  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
19  */
20 
21 /*
22  * ====================================================
23  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
24  *
25  * Developed at SunPro, a Sun Microsystems, Inc. business.
26  * Permission to use, copy, modify, and distribute this
27  * software is freely granted, provided that this notice
28  * is preserved.
29  * ====================================================
30  */
31 
32 
33 #ifdef POK_NEEDS_LIBMATH
34 
35 /*
36  * wrapper log2f(X)
37  */
38 
39 #include <libm.h>
40 #include "math_private.h"
41 
42 
43 float
44 log2f(float x) /* wrapper log2f */
45 {
46 #ifdef _IEEE_LIBM
47  return __ieee754_log2f(x);
48 #else
49  float z;
50  z = __ieee754_log2f(x);
51  if(_LIB_VERSION == _IEEE_ || isnanf(x)) return z;
52  if(x<=(float)0.0) {
53  if(x==(float)0.0)
54  /* log2(0) */
55  return (float)__kernel_standard((double)x,(double)x,148);
56  else
57  /* log2(x<0) */
58  return (float)__kernel_standard((double)x,(double)x,149);
59  } else
60  return z;
61 #endif
62 }
63 
64 #endif